diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index c62e2c559..e0e91dfb0 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,3 +1,8 @@
+**2.3.1 - 3/11/24**
+
+ - Update Mortality Observer to include tracked in population filter
+ - Fix bug in get_initialization_parameters to only remove existing keys if necessary
+
 **2.3.0 - 3/7/24**
 
  - Update population configuration keys to be more descriptive
diff --git a/src/vivarium_public_health/disease/state.py b/src/vivarium_public_health/disease/state.py
index b54db761a..0f57b9420 100644
--- a/src/vivarium_public_health/disease/state.py
+++ b/src/vivarium_public_health/disease/state.py
@@ -85,8 +85,9 @@ def on_initialize_simulants(self, pop_data: SimulantData) -> None:
     def get_initialization_parameters(self) -> Dict[str, Any]:
         """Exclude side effect function and cause type from name and __repr__."""
         initialization_parameters = super().get_initialization_parameters()
-        del initialization_parameters["side_effect_function"]
-        del initialization_parameters["cause_type"]
+        for key in ["side_effect_function", "cause_type"]:
+            if key in initialization_parameters.keys():
+                del initialization_parameters[key]
         return initialization_parameters
 
     def get_initial_event_times(self, pop_data: SimulantData) -> pd.DataFrame:
diff --git a/src/vivarium_public_health/metrics/mortality.py b/src/vivarium_public_health/metrics/mortality.py
index fcb2e9c9e..8f527e33c 100644
--- a/src/vivarium_public_health/metrics/mortality.py
+++ b/src/vivarium_public_health/metrics/mortality.py
@@ -78,14 +78,18 @@ def setup(self, builder: Builder) -> None:
         self._cause_components = builder.components.get_components_by_type(
             (DiseaseState, RiskAttributableDisease)
         )
-
+        self.causes_of_death = ["other_causes"] + [
+            cause.state_id for cause in self._cause_components if cause.has_excess_mortality
+        ]
+        self.required_death_columns = ["alive", "exit_time"]
+        self.required_yll_columns = [
+            "alive",
+            "cause_of_death",
+            "exit_time",
+            "years_of_life_lost",
+        ]
         if not self.config.aggregate:
-            causes_of_death = ["other_causes"] + [
-                cause.state_id
-                for cause in self._cause_components
-                if cause.has_excess_mortality
-            ]
-            for cause_of_death in causes_of_death:
+            for cause_of_death in self.causes_of_death:
                 self._register_mortality_observations(
                     builder, cause_of_death, f'cause_of_death == "{cause_of_death}"'
                 )
@@ -100,15 +104,15 @@ def _register_mortality_observations(
         self, builder: Builder, cause: str, additional_pop_filter: str = ""
     ) -> None:
         pop_filter = (
-            'alive == "dead"'
+            'alive == "dead" and tracked == True'
             if additional_pop_filter == ""
-            else f'alive == "dead" and {additional_pop_filter}'
+            else f'alive == "dead" and tracked == True and {additional_pop_filter}'
         )
         builder.results.register_observation(
             name=f"death_due_to_{cause}",
             pop_filter=pop_filter,
             aggregator=self.count_deaths,
-            requires_columns=["alive", "exit_time"],
+            requires_columns=self.required_death_columns,
             additional_stratifications=self.config.include,
             excluded_stratifications=self.config.exclude,
             when="collect_metrics",
@@ -117,12 +121,7 @@ def _register_mortality_observations(
             name=f"ylls_due_to_{cause}",
             pop_filter=pop_filter,
             aggregator=self.calculate_ylls,
-            requires_columns=[
-                "alive",
-                "cause_of_death",
-                "exit_time",
-                "years_of_life_lost",
-            ],
+            requires_columns=self.required_yll_columns,
             additional_stratifications=self.config.include,
             excluded_stratifications=self.config.exclude,
             when="collect_metrics",